Export of Staphylococcal Toxins by a Conserved ABC Transporter

Staphylococci are important human pathogens. Several of these, first and foremost Staphylococcus aureus, rely on the secretion of phenol-soluble modulins (PSMs) to establish infections in a variety of disease types. PSMs are amphipathic, α-helical peptides with broad sequence diversity and a variety of functions in the infectious and non-infectious lifestyles of staphylococci. For example, many PSMs are strongly cytolytic, and most of them have pro-inflammatory capacities. Furthermore, PSMs help structure biofilms and promote the dissemination of biofilm-associated infection throughout the body. PSMs are secreted non-canonically by a recently discovered and dedicated ABC transport system named Pmt. Consisting of two membrane-spanning and two ATPase proteins, Pmt is conserved among all staphylococci. This review describes the discovery, features, and putative mechanism of Pmt. Furthermore, it discusses the potential of using the Pmt system as a single target to abolish secretion of all PSMs for virulence-oriented anti-staphylococcal therapy.